An opacifier is an ingredient included in a composition to reduce or eliminate the clear or transparent appearance of the composition. An opacifier often is included in a composition to mask an undesirable esthetic property, such as to improve the color of a composition that is darkened due to the presence of a particular ingredient, or to mask the presence of particulate matter in the composition. Opacifiers also are included in aqueous compositions to improve the esthetics and consumer acceptance of an otherwise esthetically-unacceptable composition. For example, an opacifier can impart a pearlescent appearance to a clear composition, thereby communicating an appearance of creaminess, mildness and body to the consumer. In addition, an opacifier also can impart other advantageous properties to a composition, such as thickening, suspending and emulsifying properties.
Opacifiers commonly are included in hair care compositions, such as hair shampoos, hair conditioners and combination hair shampoo-conditioners. Opacifiers also are included in skin care compositions, such as skin moisturizers, skin conditioners and topical medicaments. In general therefore, an opacifier is a compound that gives a composition either more opaque or pearlescent appearance, and does not otherwise adversely affect the composition or the usefulness of the composition.
An opacifier can be selected from a number of different chemical classes including inorganic compounds, e.g., various aluminum and magnesium salts, and organic compounds, like fatty alcohols, fatty esters and various polymers and copolymers. A representative listing of opacifiers is found in the CTFA Cosmetic Ingredient Handbook, J. Nikitakis, ed., The Cosmetic, Toiletry and Fragrance Association, Inc., Washington, D.C., 1988, at page 75.
The present invention is directed to a new class of opacifying compounds that impart a velvety pearlescent effect to water-based compositions, and that provide the added benefits of effectively resisting phase separation and of assisting the suspension of water-insoluble ingredients in a water-based composition. The new opacifiers are useful in topical compositions, like hair care and skin care products; in topical medicaments; and in other water-based compositions, such as cleaning compositions for hard surfaces.
While numerous compositions that include opacifiers have been disclosed, the present invention is directed to a new class of opacifying agents. Some of these previously-disclosed opacifiers are described in patents issued in the shampoo area. In particular, Oh et al., in U.S. Pat. No. 4,704,272, disclose shampoo compositions including an anionic surfactant, a nonvolatile silicone, a hair conditioning agent and a suspending agent. The hair conditioning agent can be a tri-long chain (C.sub.8 -C.sub.22) amine, such as tri(isodecyl)amine or tri-C.sub.13 amine, Oh et al. also teach that a suspending agent, like a xanthan gum or a long chain acyl derivative, is essential to the composition, and that the suspending agent may impart pearlescence to the composition. Oh et al. do not teach or suggest that a long chain amine imparts pearlescence to the product. Surprisingly, it has been found that a primary, secondary or tertiary amine including at least one carbon chain having at least sixteen carbon atoms or an amidoamine including a carbon chain having at least thirteen carbon atoms, neutralized with a suitable acid, imparts excellent pearlescence to the composition and helps provide a stable shampoo composition that effectively resist separation of the water-insoluble hair-treating compound from the shampoo compositions without the need for a separate suspending agent. Grote et al. U.S. Pat. No. 4,741,855; Oh GB Patent 2,177,108A; and Fieler et al. U.S. Pat. No. 4,728,457 similarly teach that an amine oxide or long chain acyl derivative may impart pearlescence. None of these patents teaches a long chain amine salt as an opacifier.
Bolich et al., in U.S. Pat. No. 4,472,375, disclose an aqueous hair-conditioning composition comprising a volatile hydrocarbon or a volatile silicone; a nonionic thickening agent; a quaternary ammonium salt and/or a salt of a fatty amine. The composition disclosed by Bolich et al. does not include the fatty amine salt as an opacifier. Bolich et al. do not teach or suggest the use of a fatty amine salt is an opacifier.
As will be demonstrated more fully hereinafter, an opacifier comprising: a) a fatty amine having at least one alkyl group including at least about sixteen carbon atoms or a fatty amidoamine having an alkyl group including at least about thirteen carbon atoms, and b) a suitable acid, effectively opacifies or pearlizes a water-based composition without adversely affecting the composition; effectively resists phase separation from the composition; and effectively assists in suspending a water-insoluble compound present in the water-based composition to allow a more efficient topical delivery of the water-insoluble compound to the hair, scalp or skin.